1. Field of the Invention
The present invention relates to a system for evulsing subcutaneous tissue represented by a subcutaneous blood vessel, such as a saphenous vein, by using an endoscope.
2. Description of the Related Art
When, for example, an operation for bypassing a blood vessel in the heart is performed, a saphenous vein existing in the leg of the body is extracted in order to use the saphenous vein as a bypass blood vessel. When the saphenous vein is extracted, an operation for separating the saphenous vein from other textures is initially required. The upper texture of the saphenous vein has a structure formed by sequentially stacking the connective tissue covering the saphenous vein, and fat and the skin formed on the connective tissue.
When an operation for extracting the subcutaneous blood vessel, such as the saphenous vein in the lower extremity, is performed, the skin is incised along the blood vessel below the skin with, for example, a knife. Then, the subcutaneous tissue, such as the panniculus adiposis, in the lower layer of the skin and the connective tissue on the blood vessel are incised so that the blood vessel having a length intended to be extracted is exposed. The two ends of the exposed blood vessel are is cut and taken out to the outside of the body. However, the extracting operation results in the skin being considerably incised, and an excessively long time is required for the patient to be cured. What is worse, the incised portion is scarred and hardened, thus causing a problem in that the patient has a cramp in the leg when he moves the leg and thus the patient feels a pain.
Accordingly, it might be considered feasible to extract the subcutaneous blood vessel, such as the saphenous vein, through a small cut portion on the skin in the lower extremity. The other methods for extracting the subcutaneous blood vessel, such as the saphenous vein, through a small cut portion of the skin have been disclosed in, for example, U.S. Pat. No. 4,793,346 and U.S. Pat. No. 5,373,840. Especially, the method disclosed in U.S. Pat. No. 5,373,840 is concerned with extracting the subcutaneous blood vessel by using an endoscope.
The method disclosed in U.S. Pat. No. 4,793,346 has the steps of incising the skin of the lower extremity; inserting, through the incised portion, a tube having an inner diameter somewhat larger than the outer diameter of the vein; and allowing an electric current to flow through a knife disposed at the leading end of the tube, so that the tube is moved forwards while being rotated. As a result, the side branches of the vein are cauterized and cut by the knife so that the vein is extracted.
The method disclosed in U.S. Pat. No. 5,373,840 is arranged to use an endoscope having a channel extending longitudinally to take out an end of the blood vessel, to be extracted, through a cut portion of the body of a patient. Thus, the blood vessel is held by a grip means through the channel of the endoscope and the blood vessel is removed by cutting.
However, the method disclosed in U.S. Pat. No. 4,793,346 is a method of blindly moving forwards the tube having the knife. Therefore, the foregoing method has a risk of the saphenous vein, intended to be extracted, being undesirably cut in addition to the fact that the saphenous vein is not straight in general. Moreover, the method has a risk of the saphenous vein being burnt thermally due to the electric current allowed to flow from the knife.
With the method disclosed in U.S. Pat. No. 5,373,840, the endoscope is moved forward along the blood vessel and any one of a variety of treatment tools is inserted into the body through the channel of the endoscope. Then, the tissue is ablated by the treatment tool while being observed through the endoscope so that the blood vessel is treated. Therefore, a too complicated operation is required and a long time is required to complete the operation. What is worse, if the objective lens of the endoscope is contaminated with blood or the like, a complicated operation is required in which all of the devices are removed to the outside of the body.
In a case where the skin is cut to permit the endoscope and the treatment tool to be inserted into the lower extremity through the cut portion so as to extract the subcutaneous blood vessel, a cavity is required around the subcutaneous blood vessel because the blood vessel exists under the skin in which no cavity exists. That is, the blood vessel and the other portions including the connective tissue are required to be considerably apart from each other so as to form a working space between the blood vessel and the connective tissue to extract the blood vessel. However, a cavity cannot easily be formed around the subcutaneous blood vessel because the subcutaneous tissue, such as the panniculus adiposis, and the connective tissue on the blood vessel exist around the subcutaneous blood vessel.
A cannula for forming a cavity, into which the endoscope and the treatment tool can be inserted, in the body and which permits treatment and observation of a diseased part to be performed in the cavity with the endoscope has been disclosed in, for example, WO93/10704. The cannula has a body formed into a cylindrical shape having two opened ends. Moreover, a slit is formed along the axis of the cylindrical body of the cannula. The cannula is used such that the leading end of the body of the cannula is introduced into the body through an incised portion of the skin, and then its leading end is discharged to the outside of the body through another incised portion so that the two end openings are exposed and thus a cavity is formed in the body cavity. After the cavity has been formed in the body cavity by the cannula, the endoscope is introduced into the cannula through one of the openings of the body of the cannula, that is, into the cavity formed by the cannula. Moreover, a treatment tool is, through another opening or the slit of the body of the cannula, introduced into the cavity formed by the cannula. Thus, while observing the diseased part through the endoscope, the diseased part can be treated by the treatment tool.
Although the cannula is suitable to be in an operation for ablating a diseased part in the fibrous tissue as is performed in surgical treatment of a carpal tunnel syndrome, the cannula is unsuitable to be in an operation for extracting the subcutaneous blood vessel, such as the saphenous vein in the lower extremity, because a satisfactorily large cavity cannot be formed. If a satisfactorily large cavity cannot be formed, the endoscope and the treatment tool inserted into the cavity cannot easily be manipulated. Thus, the subject tissue and the surrounding tissues can easily be damaged.
As described above, the operator must pay great attention to protect the subcutaneous tissue from being damaged when the operator treats a portion in the vicinity of the subcutaneous tissue, such as the blood vessel and the nerve. However, the ablating operation and the incising operation, to be performed just above the saphenous vein intended to be extracted, have a risk of the saphenous vein being damaged by the treatment tool or the like during the operation. The operation for forming a cavity under the skin has a similar risk. The saphenous vein for use as a bypass blood vessel in the heart is required to be extracted while being protected from any damage. The foregoing requirement is not limited to the extraction of the saphenous vein. Also the same requirement arises in any case where the tissues, which must be protected, exist near the portion in which a treatment operation is performed.
On the other hand, a technique has been developed which has an arrangement such that a hood is attached to the insertion portion of the endoscope to protect an observation window of the endoscope from being contaminated due to adhesion of the tissue of the organism to the observation window and to form a space which permits an observation to be performed with the endoscope when the tissue of the organism, such as the subcutaneous tissue, having no cavity therein is observed and treated by using the endoscope. The foregoing objects are important facts when the subcutaneous tissue is evulsed.
The applicant of the present invention has applied a sheath which serves as the hood to be attached to the insertion portion of the endoscope and which has a cylindrical shape having an opened leading end (refer to Japanese Patent Application No. 7-172466 published as Japanese Patent Laid-Open No. 8-117181) and a hood having a shape capable of completely covering the endoscope and suitable to excise the tissue (refer to Japanese Patent Application No. 7-172139). Moreover, a hood has been disclosed in Japanese Patent Publication No. 4-10328, the hood having an opening formed on the side surface thereof for permitting a treatment tool, such as a knife, to be inserted through the opening. Another hood has been disclosed in WO94/11052, the hood having a tubular body, into which the endoscope is inserted and which has the end that can be opened for permitting a visual field to be maintained for the endoscope when the observation and treatment are performed. In Japanese Patent Publication No. 4-17648, a hood having a window which can be opened and closed for the treatment tool has been disclosed. In relation to the hoods disclosed as described above, a tracheal unit consisting of an outer tube and an internal needle has been disclosed in Japanese Utility Model Publication No. 61-7686 (corresponding to Laid-Open Publication No. 56-166006, the internal needle of the tracheal unit having a HF electrode attached thereto. In Japanese Patent Laid-Open No. 5-161660, a tracheal unit having a transparent leading end has been disclosed. The tracheal unit is combined with an endoscope and a laser beam unit.
As described above, in recent years, the treatment using an endoscope has been performed in a portion in which no cavity exists, as has been performed when the blood vessel in the human body is treated. In this case, also a technique is employed in which any of the various hoods is attached to the insertion portion of the endoscope; and the endoscope is moved forward while excising the portion between the tissues of the organism having no cavity. If the hood abuts against, for example, the fasciae between muscles during the operation of inserting the endoscope, only a sluggish operation using the hood encounters a great difficulty in incising the fasciae. If bleeding takes place unintentionally during the operation for excising the tissue, hemostasis is required. However, the conventional techniques cannot smoothly solve the foregoing problems.
That is, the technique disclosed in Japanese Patent Application No. 7-172139. permits only a sluggish operation to be performed such that the leading end of the hood is forcibly inserted into the tissue of the organism when, for example, an operation for incising the fasciae between the muscles is performed. Thus, the technique encounters a problem in that the operation efficiency cannot be improved. Moreover, when hemostasis of a bleeding portion is intended, a complicated operation is required such that another hemostasis means is, in parallel, inserted between tissues. The hood disclosed in Japanese Patent Publication No. 4-10328 and having the opening in the side surface thereof cannot effectively incise and/or excise the tissue of the organism in front of the endoscope in the case where the treatment tool, such as a knife, is inserted through the opening. Moreover, since no hemostasis means is provided, hemostasis of the bleeding portion cannot effectively be performed. Although the techniques disclosed in Japanese Patent Laid-Open No. 8-117181, Japanese Patent Publication No. 4-17648 and WO94/11052 are able to solve the foregoing problems by inserting an incising tool and a hemostasis tool into the body through the treatment tool channel of the endoscope, another problem arises in that the operation for inserting and drawing the treatment tool to and from the treatment tool channel of the endoscope and the operations of the treatment tools are too complicated. Since the technique disclosed in WO94/11052 has the structure such that the tubular body into which the endoscope is inserted is not transparent, the excising operation is required to be blindly performed. Thus, the operation cannot easily be completed and a problem arises in keeping safety.